AMR â€“ much more than billing data
Developments in automatic meter reading (AMR) for the supply of electricity have challenged energy companies to expand on AMR initiatives, forcing them to look beyond the commercial aspect for billing purposes.
In this article, ‘going beyond the commercial aspects’ will be referred to as additional data. This additional data addresses power quality, reliability and operational aspects for the delivery of electricity. It is most relevant for industrial and commercial consumers, because they use power at a relatively high rate, with more complexity and a larger variety of loads.
AMR relates to the implementation of effective automatic metering systems, and technology trends have provided various solutions. Some examples are handheld systems and walk-by or drive-by meter readings, best achieved by wireless or fixed networks. Advances in technology of licensed and unlicensed radio, PSTN, satellite, PLC, AMPS cellular, PCS, and CDPD systems mean that utilities can choose from a wide range of communication methods.
BEYOND THE REVENUE DATA
Energy companies looking to capitalise on AMR technology are committed to replacing, upgrading or retrofitting existing meters. Billing systems may need to be upgraded at the same time. As changes to current systems are being considered, the opportunity exists to look ‘beyond the billing’ and address other meter data requirements.
Measuring data for revenue purposes involves capturing real energy, kWh, reactive energy, kVAR, and maximum demand data. The next step is to obtain data that can tell both the supplier and the consumer about the quality and reliability of the supply.
Quality and Reliability Data
Quality of electricity is a measured value, which also encompasses reliability. To monitor and report on these aspects, the following types of additional data are required:
• Voltage and current magnitudes and phase angles, along with time of minimums and maximums.
• Harmonic analysis THD and TIF.
• Event recording triggered by definable setpoints.
• Waveform capture.
• Data logging.
• Sequence of event reporting.
This data will allow companies to analyse, diagnose and mitigate a spectrum of disturbances. Power quality problems are costly to both energy supplier and consumer, and direct equipment damage is only a small portion of the overall disturbance-related costs. Unplanned outages and abnormal line losses can add significantly to the costs. This list features some of these disturbances and the factors that cause them.
• Transients – caused by lightning, ESD, and load switching.
• Sags/surges (>100ms) – caused by load switching and motor starts.
• Dropouts/outages(<30ms) – caused by load switching, fuse clearance, and arc furnace.
• Over/under voltage – caused by system overload, load shedding and transformer tap changing.
• Voltage flicker – caused by tap changing, load switching, and load variations.
• Harmonic current distortion – caused by non linear loads, and variable speed drives.
• Harmonic voltage distortion – caused by high levels of non linear current, variable speed drives, system resonance, and high system impedance.
• Low power factor – caused by motor loads and lighting systems.
• Voltage imbalance – caused by non-symmetrical load.
• Over/under frequency – caused by system overload.
Monitoring operational data will also ensure optimal delivery and receipt of electricity. Operational aspects include such things as:
• Distribution automation
• Demand side load management
• Energy monitoring and analysis
• Load shedding/transfer
• Load profiling/balancing
• Automatic capacitor bank analysis and control (power factor correction) and line loss optimisation
• Tampering/theft/outage detection
• Automatic detection of meter/communi-cation failure and outage notification
• Integration of water/gas consumption
• Network management/modeling/analysis
• Diagnostic/analysis of distribution network.
This operational data is used mainly by suppliers to provide electricity more effectively by optimising their generation, transmission, and distribution services.
If collected by an extension of the AMR system, the data can be shared or transmitted to the supplier’s overall control system. Signi-ficant savings are achieved if this information does not have to be obtained independently. However, data sharing involves co-ordinating the three major areas of electricity supply – generation, transmission and distribution.
AMR and SCADA systems
Quality, reliability and operational data have typically been available to the suppliers of electricity at the transmission level and to a certain extent in the distribution system, mainly via SCADA systems. These systems can be large and costly. The information is available to the utility company only and does not provide data to the end-user.
SCADA systems manage data that has high throughput and fast response times, as required by large generation, transmission and distri-bution networks. These requirements generally decrease with decreasing voltage levels, so the high price and high performance of a SCADA system is not necessary for most AMR applications.
An AMR system can add visibility without the SCADA price tag. The integration of AMR and SCADA makes economic sense, since the data performance requirements are matched to the actual system needs. SCADA/AMR integration gives suppliers the best value, both from an economic and a data collection point of view.
OBTAINING ADDITIONAL DATA WITH AN AMR SYSTEM
The basic data required for quality, reliability and operational aspects can be captured by advanced AMR systems. New communication technologies have made communications possible without a large capital investment. These advancements have yielded AMR solutions that cost the same as or slightly more than typical AMR additions, upgrades or new installations.
These are some of the features of today’s state-of-the-art AMR systems.
• Advanced power quality analysis and data/event recording, allowing for quick resolution of fault and harmonic disturbances on the network.
• Support for multi-tariff and time of use features, allowing for flexible billing schemes.
• Enterprise-wide data capabilities, giving accountants, engineers, operators, and consumers access to real-time information.
• Remote meter configuration, allowing for the correction/verification of ratings and voltages.
• Automatic data integration, data validation and cost allocation, which increases billing/accounting efficiency.
• Extension of system visibility from the substation to the customer.
• Automatic peak shaving/scheduling/load shedding schemes for the avoidance of demand penalties.
• Automatic power correction for efficient use of distribution/transmission networks.
• Remote connection and disconnection.
• Performance based rates implementation, where the customer pays a premium rate for a guarantee of minimum power quality.
• Real-time pricing.
• Apparent power tariffs.
When assessing an AMR system, thorough research should be conducted to understand the possible solutions for complex data collection.
BENEFITS OF THE ADDITIONAL DATA
The benefits of capturing quality, reliability and operational data are numerous, allowing energy providers to:
• Decrease labour costs.
• Improve billing accuracy and frequency.
• Obtain near real-time system performance data.
• Introduce contractual schemes to increase consumer satisfaction, while giving the energy provider additional revenue from added premium services.
• Increase accuracy while decreasing latency in the diagnosis and resolution of network disturbances.
• Plan for future needs.
• Obtain on-demand meter reads.
• Perform system disturbance diagnosis by recording event sequences.
• Provide automatic multi-site energy aggregation and billing.
• Perform transformer and line loss cal-culations on a per meter basis.
Each AMR project should look at the basic metering needs in conjunction with the advanced data requirements. The benefits can be tremendous, given the relatively low costs.
One recent development in the AMR field is the use of the World Wide Web to gain access to metering data, offering these benefits.
• Web access is economical – low equipment costs, plus no host associated costs (no hardware, no software, no set-up).
• Web access is hostless – system operation can be accomplished with any web browser, from anywhere in the world.
• Web access is plug and play – simply install the box and connect the wires.
• Web access is flexible – it is independent of specific communication systems and will work with most communication in-frastructures.
• Web access is scaleable – no expensive communication infrastructure means that it is as economically viable for one unit as for one hundred.
• Web access is accessible – alarms and disturbances are reported to a medium of choice (e-mail, pager, PCS, PSTN or cellular).
This new technology is constantly under development; it is important to monitor the trends as they occur in order to gain full benefit.
CAPITALISE ON THE NEW DEVELOPMENTS
The additional data is most relevant for industrial and commercial consumers, who – unlike residential customers – have an impact on the electric supply because of their diverse application of electricity. Energy suppliers considering an AMR project should look not only at the basic metering needs of these consumers, but also at their advanced data requirements. A thorough study should be performed to identify what is currently available, what is required, what to consider for the future, and what it will take to get there.
A study of this nature is best performed with an understanding of the automation and control aspects of electric generation and distribution. Understanding the quality, reliability and operational impacts requires a background in electric utility generation, transmission, distribution, automation and control systems.
AMR is a great starting point for the use of technology in improving competitiveness. It is an opportunity to build a system that is compre-hensive and flexible, a system that can capitalise on billing, quality, reliability and operational advancements. Think beyond the billing data.